So my finance professor got pissed off because someone went behind her back and talked to the dean about how bad of a teacher she is because a lot of people are failing her class.

She responds by telling us she'll give us extra credit if we FIND THE BIBLE VERSE that talks about confronting a person before going over their head to superiors. I've looked for about 20 minutes, can't find it. Any ideas what it could be? I thought Proverbs 11:12-13.